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Author Topic: Valve & rocker wear.  (Read 3292 times)

LarsBloodbeard

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Valve & rocker wear.
« on: November 08, 2012, 06:22:58 AM »
Been adjusting my pushrod longer every morning for the past couple days.  Thought maybe the pushrod was collapsing or bending, but this morning I adjusted it again and there was still a loud tap-tap-tapping as if it had a lot of slop.  Also it ran like crap.  So this evening I pulled the pushrod access panel off and slowly rotated the engine with the kicker and it clicked with every downstroke of the exhaust pushrod.  I took the valve cover off & the rocker, and here's what I saw.... What happened here?!  Note: I just had a valve job done by a reputable machinist.

LarsBloodbeard

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Re: Valve & rocker wear.
« Reply #1 on: November 08, 2012, 06:43:52 AM »
Here's the other side, for comparison.  The valve cap isn't squished like a pancake, but the rocker is showing signs of fresh wear.

Bullet Whisperer

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Re: Valve & rocker wear.
« Reply #2 on: November 08, 2012, 09:32:34 AM »
Any chance of some close ups of the rocker tips - where they make contact with the valve stem? From what I can see at the moment, your rocker tips look like nothing I have seen before on an Enfield and it makes me wonder if they have been messed with?
 B.W.

ace.cafe

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Re: Valve & rocker wear.
« Reply #3 on: November 08, 2012, 01:53:01 PM »
Well, with that kind of problem with the exhaust side, you are going to have to re-check the valve guide to be sure it hasn't been harmed by that. Assuming the valve guide is still in-spec, you really only have to fix the valve parts that are bad, and get new rockers. Perhaps pushrods, if they are bent like you mentioned.
I'd recommend getting the Samrat rockers, and drilling out the oil hole in the rocker blocks from 2mm standard size hole, up to 1/8" or 3mm size hole. It's an aluminum block design, very easy to drill, and the holes are very short. It's an easy home job. The Samrat rockers are better designed.

That's a fairly unusual thing that you had happen there. I have seen some failures in that area, but not so severe. From what I have seen before, if it has been getting that bad for a while, it could transfer the damage to the pushrod, which we have seen. And it is also possible to have some damage transfer down to the lifter and to the cam. In the last Bullet I saw with lesser problem, but similar, the pushrod was bent, and the cam nose had unusual wear. The lifter seemed to have been spared. These things should all be looked at, if possible.

Regarding those rockers, I have seen some Bullet rockers like that. Your intake side rocker pad pattern seems fairly normal, if a bit long. This exposes the typical wrong rocker geometry that is seen on Bullets. But, it isn't bad, and it's centered, and it's not falling off the valve lash cap. The further that wear pattern goes toward the edge, the more side-force is placed on the valve, causing higher valve guide wear than necessary.
I would say that virtually all street Bullets suffer from some "less than ideal" rocker geometry issues.

It won't be a terribly expensive fix, and it's not a very labor intensive job to fix these things that have gone bad. It's not really all that bad in the overall scheme of things that can go wrong with a Bullet.
« Last Edit: November 08, 2012, 02:04:41 PM by ace.cafe »

ERC

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Re: Valve & rocker wear.
« Reply #4 on: November 08, 2012, 02:15:22 PM »
Looks like the valve keeper let the valve get pushed down in the spring.  ERC
2-57 Apaches, 2-57 Trailblazers, 60 Chief, 65 Interceptor, 2004 Bullet, 612 Bullet chopped.

LarsBloodbeard

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Re: Valve & rocker wear.
« Reply #5 on: November 08, 2012, 04:07:41 PM »
Thanks, guys.  Would this be the fault of the machine shop?  Or just a random failure?  These were fine 80 miles ago.  The valve tip collapsing into the spring makes a lot of sense as to why I suddenly had to lengthen my pushrod.

ace.cafe

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Re: Valve & rocker wear.
« Reply #6 on: November 08, 2012, 04:13:51 PM »
Thanks, guys.  Would this be the fault of the machine shop?  Or just a random failure?  These were fine 80 miles ago.  The valve tip collapsing into the spring makes a lot of sense as to why I suddenly had to lengthen my pushrod.

It's very difficult to say. Maybe there will be more clues when you get it apart.
The tapered arrangement with which these valves are attached to the upper spring retainer is very hard to get it wrong. They pull themselves together.  But I guess incorrect assembly could somehow be possible. Or a combination of a partially failing part not being noticed by the assembler, and then a failure there after.

It could be various reasons, one of which is that the parts often aren't too great to begin with.

ERC

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Re: Valve & rocker wear.
« Reply #7 on: November 08, 2012, 05:43:13 PM »
Like Ace says take it apart I think the reason for it will be obvious.   ERC
2-57 Apaches, 2-57 Trailblazers, 60 Chief, 65 Interceptor, 2004 Bullet, 612 Bullet chopped.

Chasfield

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Re: Valve & rocker wear.
« Reply #8 on: November 08, 2012, 06:45:56 PM »
Looks like quite a lot of powdered steel could have washed down into the timing case. Maybe a good idea to pull the cover off and clean out with solvent. Inspect the condition of the oil pump drive while you are in there.

Did the exhaust valve stem cap jump out and leave the the softer valve stem to be eaten away by the rocker? If so, where did the cap finish up. Or was one actually fitted?

It looks like the valve stem is eaten away down to the collets and ready to let go, so the assembly should be treated with caution until a valve spring compressor has been applied.
2001 500 Bullet Deluxe

LarsBloodbeard

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Re: Valve & rocker wear.
« Reply #9 on: November 08, 2012, 09:19:07 PM »
Good idea, Chasfield.  I need to check the condition of the cams anyway.  I looked around in the head and didn't see anything.  I don't have a spring compressor, unfortunately.  Shopped around for one at the local parts stores and nobody had one that would work.  Tomorrow I'll take it down to the machine shop and have them pop the valves out.  Then we'll see what went on there...

Arizoni

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Re: Valve & rocker wear.
« Reply #10 on: November 08, 2012, 09:48:14 PM »
Admittedly, my Iron Barrel manual is for an old British engine but it clearly shows a cylindrical steel "stem cap" sitting against the end of the valve above the split collars.

I assume the Indian engines have a similar cap in their engines?

The nose of the rocker arm pushes against this (I assume, hardened) steel cap.

The exhaust valve in the photo looks like the rocker arm has been pushing directly against it, hence the excessive wear on the stem.

Were these hardened steel "stem caps" in the upper spring retainers pocket between the rocker arms and the valve stems?
If not, there is the source of the problem.
Jim
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1999 Miata 10th Anniversary

ERC

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Re: Valve & rocker wear.
« Reply #11 on: November 08, 2012, 10:40:15 PM »
Most of the Bullets have the caps, unless the shop that did the job used different valves. It's possible they threw the valves in a pile and the caps got lost.  ERC
2-57 Apaches, 2-57 Trailblazers, 60 Chief, 65 Interceptor, 2004 Bullet, 612 Bullet chopped.

ace.cafe

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Re: Valve & rocker wear.
« Reply #12 on: November 08, 2012, 11:19:57 PM »
The lash cap appears to be in position on the intake valve picture.
I can't tell what's there in that crushed mess on the exhaust valve.
It just needs to be disassembled and inspected.

Arizoni

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Re: Valve & rocker wear.
« Reply #13 on: November 08, 2012, 11:56:48 PM »
Your eyes must be better than mine.

In the two pictures of the intake valve I think I clearly see the two split collars and the end of the valve stem?

I picture (in my mind) the stem cap as being a cylindrical disk that fits nicely into the pocket in the upper part of the valve spring retainer.
It should have a nicely ground finish on both faces.

IMO, if it were in place I wouldn't be able to see the end of the valve stem or the split collars but what do I know?   :D
Jim
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ace.cafe

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Re: Valve & rocker wear.
« Reply #14 on: November 09, 2012, 01:15:13 AM »
Here's a picture of what they look like.


They snap over the top of the valve tip on top.
« Last Edit: November 09, 2012, 01:29:45 AM by ace.cafe »